Field
Embodiments described herein relate generally to a power amplifying device.
Background Art
Power amplifying devices for car audio equipment typically have a B-class or AB-class bridge circuit configuration and are installed in a limited space. The car audio equipment has problems in that it is difficult to install a large heat radiating device, such as a radiator fin, and semiconductor devices of the audio equipment are damaged by heat and have a reduced life time.
Recent car audio equipment tends to have higher power and more channels and to be multimedia-ready. In this trend, there is an increasing demand for a high-efficiency power amplifier system that generates less heat.
One of common on-vehicle power amplifying devices having a single power supply rail is a power amplifying device of a multi-stage vertical configuration.
With the multi-stage vertical configuration, however, the single power supply rail needs to be divided into multiple stages to produce a bias voltage, and each of the bridge amplifiers vertically stacked needs to be driven within the range of the bias voltage.
Therefore, if the power supply voltage is low, the voltage applied to the bridge amplifier is also low, and it is difficult to achieve bridge amplification.
Thus, the conventional power amplifying devices have a problem in that it is difficult to further reduce the consumed current.